Dielectric relaxation phenomena of polysubstituted benzenes under high frequency electric field

The relaxation times τ j 's and the dipole moments μ j 's in SI units of polysubstituted benzenes like meta-diisopropylbenzene, para-methylbenzoylchloride and ortho-chloroacetophenone in benzene are estimated at 30°, 35°, 40° and 45 °C from the real k ′ ij imaginary k ″ ij parts of the dimensionless complex hf dielectric constants k * ij measured under 3 cm wavelength electric field. τ j 's measured from the ratio of the slopes of the variations of imaginary σ ″ ij and real σ ′ ij parts of complex hf conductivity σ * ij with the weight fractions w j 's in the limit w j = 0 at a given temperature are reliable in comparison to the linear coefficients of variation of σ ″ ij against σ ′ ij of different w j 's (Murthy et al 1989). In the former case the polar-polar interactions are fully eliminated. The thermodynamic energy parameters with the estimated τ j 's reveal the cooperative process for p-methylbenzoylchloride unlike other two molecules besides the solute-solute and solute-solvent molecular associations. The variation of μ j 's with temperature in °C when compared to theoretical dipole moments μ theo 's from available bond angles and bond moments establishes the temperature dependence of the inductive, mesomeric and electromeric effects of the substituted polar groups of molecules.